This invention lies in the field of bolt action firearms. In particular the invention relates to the bolt action of rifles as epitomised, for example, by the Mauser bolt action. The bolt action consists of a bolt moving back and forth in a receiver and held in the position in which it shuts the chamber by locking its handle or lugs against an abutment in the receiver with a quarter turn of the bolt.
The Inventor is aware that presently most bolt action rifles are made for right handed users, i.e. the right hand is used for operating the bolt, the face and body are to the left of the rifle and spent cartridges are ejected to the right There are, however, some bolt action rifles made exclusively for left handed users, i.e. the left hand is used for operating the bolt, the face and body are to the right and spent cartridges are ejected to the left.
It is a recognised problem in the art that when a left handed user uses a right hand bolt operation rifle (or less commonly a right handed user uses a left hand bolt operation rifle), the use is awkward and there is a risk of injury to the user. This is due to a tendency for the user to place the face and body on the side to which spent cartridges are ejected from the rifle.
A large number of existing bolt action rifles are based on the Mauser K98 action which consists of a bolt with a handle which is an integral part of the bolt, on the right hand side to be operated normally with the right hand and a receiver within which the bolt is axially displaceable. With the bolt in the firing position, the bolt handle is down to the right of the action and two or more lugs on the bolt locate into recesses inside the receiver holding the chamber closed with the cartridge inside.
To eject a spent cartridge and load a new round the bolt handle is lifted upwards rotating the bolt anti-clockwise through 90 degrees. During this rotation a part of the bolt or bolt handle engages an angled surface or cam surface on the receiver forcing the bolt rearwards. This is known as the primary extraction which is very important as the leverage obtained against the cam surface is designed to release cartridge cases that may get stuck after firing due to dirt or over pressure etc. Once the bolt reaches the full 90 degree travel the lugs inside the receiver are freed from the recesses and located in slots which allow the bolt to be pulled to the rear of the action. The rearward movement of the bolt brings with it the cartridge case the rim of which is gripped by the extractor at the front of the bolt. As the bolt approaches its complete rearward travel the cartridge case is ejected out of the right hand side of the action by means of an ejector which is a sprung component either set in the head of the bolt or in the side of the action.
Generally when a left handed rifle is required the whole action and bolt has to be built the opposite way around or mirror reversed, allowing the left handed person to be able to operate the weapon with his left hand rotating the bolt clockwise to open the bolt.
Such left handed bolt actions are few and far between and tend to be extremely expensive as not many manufacturers make them and those that do in small quantities. More often than not when a left handed person requires a rifle he is obliged to settle for a normal right handed action fitted with a left handed stock.
A solution of these problems according to the invention is to provide a bolt action for a firearm which is configured to be interchangeably useable by left handed and right handed users.
The bolt action includes a receiver, a bolt axially displaceable within the receiver, a bolt handle for the bolt, formations for locking the bolt in a position in which it doses the chamber of the firearm, extractor and elector means in the action, a firing pin in the bolt, characterised in that the receiver and/or bolt have/has cam surfaces oriented for primary extraction both by clockwise and anti-clockwise rotation of the bolt, the receiver has apertures for spent cartridge ejection to both left and right hand sides of the firearm and the handle is oriented relative to the bolt for configuration either to the left hand or right hand of the bolt.
The bore of the receiver may include a guide slot or slots and the bolt a co-acting lugs or lugs. The guide slot(s) extend(s) longitudinally along the bore of the receiver for movement of the bolt back and forth and circumferentially both clockwise and anti-clockwise in the bore for locking the action by e.g. a quarter turn. If there are two slots they must be in two angularly separated positions, similarly if there are two lugs. There may be both two slots and two lugs. There may be two (or more) axially separated sets of lug(s) and slot(s), to provide better assurance against failure of the lug(s) due to overpressure, etc.
The receiver may have a circumferential slot for a co-acting lug or lugs on the bolt handle or a co-acting neck of the handle located adjacent the bolt in use.
These arrangements permit the bolt handle to be oriented relative to the bolt so that the bolt can be used to rotate the bolt to the left or to the right, as desired, for left hand or right hand axial displacement of the bolt.
The bolt handle may be oriented relative to the bolt by being removable from the bolt for reattachment in the desired left hand or right hand configuration. This reattachment may be by insertion into the same hole in the bolt with the handle rotated either to left or to right i.e. by one hundred and eighty degrees. In a preferred embodiment there are two holes in the bolt for insertion of the handle into one for right hand use and into the other for left hand use. These two holes in the bolt may be one hundred and eighty degrees angularly separated from each other. The holes may be given a non-symmetrical shape to ensure that the handle is correctly inserted in each case. Other formations than holes may be provided for attaching the handle to the bolt.
An alternative arrangement may be for the handle to remain attached to the bolt but be rotated in its attachment to a position for left hand use or to a position for right hand use.
The cam surfaces may be provided either on the receiver, in the slots in the bore of the receiver, on the bolt, on the lugs on the bolt or on the handle, with a follower on a co-acting part, or a cam surface on both co-acting parts. In a preferred embodiment the cam surfaces are provided on the receiver, positioned to act against the handle when it is attached to the bolt in either the left hand or right hand configuration. Preferably the handle has cam surfaces that act as followers of or co-act with the cam surfaces of the receiver.
The cam surfaces on the receiver may be in the form a triangular projection having an apex directed towards the rear. The triangular projection may be in the form of an equilateral triangle.
The cam surfaces may include one or more arcuate zone, for example, in the form of a pair of parabolic or hyperbolic curves meeting at an apex directed towards the rear.
The bolt handle may include a neck adjacent the bolt provided with a cam following surface. This surface may be configured complimentarily to the cam surface.
The guide slot(s) and/or lugs and/or the handle preferably have a stop member provided in a central zone of said slot(s) and/or lug(s) or other means adapted to reduce the risk of the bolt handle being rotated between the left hand and right hand configurations when this is not desired. Such undesired rotation can result in jamming or other adverse or dangerous consequence.
In one embodiment, the cam following surface of the neck of the handle is a polygon having a corner directed towards and offset from the apex of the cam surface, to reduce the risk of the bolt handle crossing over between the left hand and right hand configuration when this is not desired.
The stop member may be in the form of a cam surface or surfaces, e.g a cam surface on the receiver directed towards the rear such that when the bolt handle or a formation on the bolt engages It the bolt is rotationally displaced as it moves towards the rear, primary extraction of a cartridge in the receiver takes place and over-turning of the bolt is inhibited.
The receiver may include a pair of opposed laterally directed apertures for ejection of a cartridge from the receiver either to the right or to the left of a user, as desired, for left hand or right hand use of the bolt, respectively.
The bolt is preferably provided with cartridge extractor and ejector means at the opposite end of the bolt from the bolt handle, the extractor means being displaceable in sympathy with the bolt in conventional manner.
The receiver may include a channel in which a flange of a firing pin is located and which inhibits the firing pin from rotating as the flange is trapped within this channel. The bolt may have at its rear a chamfer which when the bolt is rotated to free it from the position in which it closes the chamber, after a shot, the rotation causes the firing pin flange to ride up this chamfer effectively pulling the firing pin rearward to cock it. This chamfer is symmetrical so that whether the bolt is rotated clockwise or anti-clockwise the firing pin will ride up this chamfer to cock the firing pin, thereby providing for left hand or right hand configuration. The sear of the firing mechanism is also located in the channel so that when the bolt is returned to close the chamber with a new round in it for the next shot, the firing pin flange engages the sear, to retain the firing pin in the cocked condition, to be released when the trigger is pulled.
The chamfer may be in the form of two chamfered portions extending from a common source, mirror-image fashion.
According to a second aspect of the invention, there is provided a receiver for a bolt action weapon, the receiver including a circumferential guide slot in the bore of the receiver for lugs on the bolt and/or for a bolt handle, which guide slot extends along a portion of the circumference of the receiver both to the left and to the right of a plane intersecting the longitudinal axis of the receiver, thereby permitting the bolt handle to be displaced along the guide slot to rotate the bolt to the left and to the right, as desired, for left hand or right hand axial displacement of the bolt.
The guide slot may have a bolt handle stop member provided in a central zone of said slot, thereby reducing the risk of the bolt handle crossing over between the left hand and right hand configuration when this is not desired.
The stop member may be in the form of a cam surface directed towards the rear of the receiver such that when the bolt handle engages and is displaced along the cam surface, primary extraction of a cartridge in the receiver takes place.
The cam surface may be in the form a triangular projection having a apex directed towards the rear. The triangular projection may be in the form of any acute angled triangle, typically an equilateral or a right angled triangle.
The cam surface may include one or more arcuate zone(s), for example, in the form of a pair of parabolic or hyperbolic curves meeting at an apex directed towards the rear.
The receiver may include a pair of opposed laterally directed apertures for ejection of a cartridge from the receiver either to the left or to the right of a user away from the user, as desired.
According to a third aspect of the invention there is provided a bolt for a bolt action weapon, the bolt including a bolt handle which is displaceable relative to the bolt for configuration of the weapon to permit either left hand or right hand axial displacement of the bolt.
The bolt handle may be removable from the bolt for reattachment in the desired left hand or right hand configuration.
The bolt handle may include a neck portion directed towards the bolt and being provided with a cam engaging surface.
The cam engaging surface may be configured complimentary to a cam surface of the weapon.
In one embodiment, the cam engaging surface of the neck portion is a polygon having a corner directed towards and offset from the apex of the cam surface, thereby reducing the risk of the bolt handle crossing over between the left hand and right hand configuration when this is not desired.
The bolt is configured such that when the bolt is displaced and rotated to the right, a cartridge is ejected to the right away from the user, and vice versa.
The bolt may be provided with a cartridge extractor portion at the bolt handle remote end of the bolt, the extractor being displaceable in sympathy with the bolt.
According to a further aspect of the invention there is provided a bolt action firearm convertible, e.g. in the field, from left handed configuration to tight handed configuration, said weapon including at least one of the action, the receiver, and the bolt, substantially as described above.